Comparative transcriptomics among floral organs of the basal eudicot Eschscholzia californica as reference for floral evolutionary developmental studies

Abstract

BackgroundMolecular genetic studies of floral development have concentrated on several core eudicots and grasses (monocots), which have canalized floral forms. Basal eudicots possess a wider range of floral morphologies than the core eudicots and grasses and can serve as an evolutionary link between core eudicots and monocots, and provide a reference for studies of other basal angiosperms. Recent advances in genomics have enabled researchers to profile gene activities during floral development, primarily in the eudicot Arabidopsis thaliana and the monocots rice and maize. However, our understanding of floral developmental processes among the basal eudicots remains limited.ResultsUsing a recently generated expressed sequence tag (EST) set, we have designed an oligonucleotide microarray for the basal eudicot Eschscholzia californica (California poppy). We performed microarray experiments with an interwoven-loop design in order to characterize the E. californica floral transcriptome and to identify differentially expressed genes in flower buds with pre-meiotic and meiotic cells, four floral organs at pre-anthesis stages (sepals, petals, stamens and carpels), developing fruits, and leaves.ConclusionsOur results provide a foundation for comparative gene expression studies between eudicots and basal angiosperms. We identified whorl-specific gene expression patterns in E. californica and examined the floral expression of several gene families. Interestingly, most E. californica homologs of Arabidopsis genes important for flower development, except for genes encoding MADS-box transcription factors, show different expression patterns between the two species. Our comparative transcriptomics study highlights the unique evolutionary position of E. californica compared with basal angiosperms and core eudicots.

Conservation and canalization of gene expression during angiosperm diversification accompany the origin and evolution of the flower

“…Specifically, we analyze transcriptome data for the water lily Nuphar advena (Nymphaeales) representing the sister lineage of all extant flowering plants except Amborella (16), the magnoliid Persea americana (avocado; Laurales), the eudicots Eschscholzia californica (California poppy; Ranunculales) and Arabidopsis thaliana (Brassicales), and the gymnosperm Zamia vazquezii (Cycadales) to help reconstruct the origin and evolution of flowers. Our analyses extend previous comparisons of floral transcriptional programs (17)(18)(19) to several additional phylogenetically significant taxa, and we present insights into the genetic relationships among individual floral organs and gymnosperm reproductive cones. To whom correspondence should be addressed.…”

Evolutionary Analysis of MIKCc-Type MADS-Box Genes in Gymnosperms and Angiosperms

“…In basal angiosperms, Eschscholzia californica , SEP may have the same functions like AP1 of A-function genes (Zahn et al, 2010). The A-class and E-class genes had two groups of orthologs in gymnosperms.…”

Developmental and evolutionary diversity of plant MADS-domain factors: insights from recent studies

“…Next to Arabidopsis, the roles of MIKC C -type genes in flower development have been extensively studied in eudicot species such as snapdragon, petunia and tomato, as well as in monocots such as rice and the orchid Phalaenopsis. Among the upcoming model species are pea (Medicago sativa) (Hecht et al, 2005) and basal eudicots such as California poppy (Eschscholzia californica) (Zahn et al, 2010). The ability to analyze gene functions in a plant species depends on the availability of tools, such as the ability to transform the plant or amenability for virusinduced gene silencing (VIGS) (Becker and Lange, 2010), and of genome and/or transcriptome resources.…”